一个国家的行政区域地图与 ggmap 和 ggplot2 [英] Administrative regions map of a country with ggmap and ggplot2

问题描述

我可以使用以下代码制作美国州级失业率图.

I can make USA state level unemployment graph with the following code.

library(XML)
library(ggplot2)
library(plyr)
library(maps)

unemp <-
  readHTMLTable('http://www.bls.gov/web/laus/laumstrk.htm',
    colClasses = c('character', 'character', 'numeric'))[[2]]

names(unemp) <- c('rank', 'region', 'rate')
unemp$region <- tolower(unemp$region)

us_state_map <- map_data('state')
map_data <- merge(unemp, us_state_map, by = 'region')

map_data <- arrange(map_data, order)

states <- data.frame(state.center, state.abb)

p1 <- ggplot(data = map_data, aes(x = long, y = lat, group = group))
p1 <- p1 + geom_polygon(aes(fill = cut_number(rate, 5)))
p1 <- p1 + geom_path(colour = 'gray', linestyle = 2)
p1 <- p1 + scale_fill_brewer('Unemployment Rate (Jan 2011)', palette  = 'PuRd')
p1 <- p1 + coord_map()
p1 <- p1 + geom_text(data = states, aes(x = x, y = y, label = state.abb, group = NULL), size = 2)
p1 <- p1 + theme_bw()
p1

现在我想为巴基斯坦绘制类似的图表.我的几次尝试结果如下:

Now I want to similar kind of graph for Pakistan. My few attempts results are below:

data(world.cities)
Pakistan <- data.frame(map("world", "Pakistan", plot=FALSE)[c("x","y")])

p <- ggplot(Pakistan, aes(x=x, y=y)) +
     geom_path(colour = 'green', linestyle = 2) +
     coord_map() + theme_bw()
p <- p + labs(x=" ", y=" ")
p <- p + theme(panel.grid.minor=element_blank(), panel.grid.major=element_blank())
p <- p + theme(axis.ticks = element_blank(), axis.text.x = element_blank(), axis.text.y = element_blank())
p <- p + theme(panel.border = element_blank())
print(p)

和

library(mapproj)

Country <- "Pakistan"

Get_Map_Country <-
  get_map(
      location = Country
    , zoom = 5
    , scale = "auto"
    , maptype = "roadmap"
    , messaging = FALSE
    , urlonly = FALSE
    , filename = "ggmapTemp"
    , crop = TRUE
    , color = "color"
    , source = "google"
    , api_key
    )

Country1 <-
  ggmap(
      ggmap = Get_Map_Country
    , extent = "panel"
  #  , base_layer
    , maprange = FALSE
    , legend = "right"
    , padding = 0.02
    , darken = c(0, "black")
    )

Country1 <- Country1 + labs(x="Longitude", y="Latitude")
print(Country1)

Country2 <- Country1 + geom_polygon(data = Pakistan
                    , aes(x=x, y=y)
                    , color = 'white', alpha = .75, size = .2)

print(Country2)

问题

我想知道如何获得美国的巴基斯坦行政区域地图.我知道为此我们需要行政边界的经度和纬度.我想知道如何获得一个国家行政边界的经度和纬度.我尝试了全球行政区，但没有成功.

I wonder how to get map of administrative regions of Pakistan as of USA. I know for this we need longitude and latitude of administrative boundaries. I'm wondering how to get longitude and latitude of administrative boundaries for a country. I tried Global Administrative Areas but without success.

推荐答案

我不知道你需要的行政区域的空间级别，但是这里有两种方法从全球行政区域 (gadm.org) 中读取 shapefile 数据和 .RData 格式，并将它们转换为数据框用于 ggplot2.此外，为了复制美国地图，您需要绘制位于多边形质心处的行政区域名称.

I don't know the spatial level of administrative areas you require, but here's two ways to read in shapefile data and .RData formats from Global Administrative Areas (gadm.org), and converting them into data frames for use in ggplot2. Also, in order to replicate the U.S. map, you will need to plot the administrative area names located at the polygon centroids.

library(ggplot2)
library(rgdal)

方法 1. SpatialPolygonDataFrames 存储为 .RData 格式

# Data from the Global Administrative Areas
# 1) Read in administrative area level 2 data

load("/Users/jmuirhead/Downloads/PAK_adm2.RData")
pakistan.adm2.spdf <- get("gadm")

方法2.用 rgdal::readOGR 读入的 Shapefile 格式

pakistan.adm2.spdf <- readOGR("/Users/jmuirhead/Downloads/PAK_adm", "PAK_adm2", 
 verbose = TRUE, stringsAsFactors = FALSE)

例如从spatialPolygonDataframes创建一个data.frame并与一个包含失业信息的data.frame合并.

pakistan.adm2.df <- fortify(pakistan.adm2.spdf, region = "NAME_2")

# Sample dataframe of unemployment info
unemployment.df <- data.frame(id= unique(pakistan.adm2.df[,'id']),
  unemployment = runif(n = length(unique(pakistan.adm2.df[,'id'])), min = 0, max = 25))

pakistan.adm2.df <- merge(pakistan.adm2.df, unemployment.df, by.y = 'id', all.x = TRUE)

提取行政区域的名称和质心以进行绘图

# Get centroids of spatialPolygonDataFrame and convert to dataframe
# for use in plotting  area names. 

pakistan.adm2.centroids.df <- data.frame(long = coordinates(pakistan.adm2.spdf)[, 1], 
   lat = coordinates(pakistan.adm2.spdf)[, 2]) 

# Get names and id numbers corresponding to administrative areas
pakistan.adm2.centroids.df[, 'ID_2'] <- pakistan.adm2.spdf@data[,'ID_2']
pakistan.adm2.centroids.df[, 'NAME_2'] <- pakistan.adm2.spdf@data[,'NAME_2']

创建带有行政区域标签的ggplot

p <- ggplot(pakistan.adm2.df, aes(x = long, y = lat, group = group)) + geom_polygon(aes(fill = cut(unemployment,5))) +
geom_text(data = pakistan.adm2.centroids.df, aes(label = NAME_2, x = long, y = lat, group = NAME_2), size = 3) + 
labs(x=" ", y=" ") + 
theme_bw() + scale_fill_brewer('Unemployment Rate (Jan 2011)', palette  = 'PuRd') + 
coord_map() + 
theme(panel.grid.minor=element_blank(), panel.grid.major=element_blank()) + 
theme(axis.ticks = element_blank(), axis.text.x = element_blank(), axis.text.y = element_blank()) + 
theme(panel.border = element_blank())

print(p)

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